Posted: Thu Mar 17, 2022 10:39pm
There is a non-double taxation agreement between the UK and Spain. So once you are tax-resident in Spain, you stop paying income tax in the UK.
(Take care though ... if you sell a UK home after you become tax-resident in Spain, you will pay capital gains tax on your profit in Spain).
There is a complication on the income tax though .... let's say you become tax-Resident in Spain on 1/1/23, you continue paying PAYE in the UK. Income tax in Spain is managed in arrears, and the tax year is Jan to Dec. You will declare your income for Jan-Dec 23, to Spain, in June 24. You will then pay that income tax in 2 chunks (June and November 24). In around Sept 24 you will apply to the Spanish authorities for a certificate confirming that you are paying tax in Spain. You then submit the certificate to HMRC, and seek release from UK income tax liability. There is a crossover period, during which you pay tax in both countries; after the certificate is cleared, you can claim back income tax paid to HMRC after 1/1/23 (you are assigned a zero-rate tax code).
Anything you draw down from your private pension after 1/1/23 will be subject to income tax in Spain at your marginal tax rate. If you draw it down before your tax certificate is cleared, you will pay in the UK and Spain, then claim it back from the UK.
FWIW, our claim-back timeline was extended by Covid and we ended up paying tax in both countries for 2 years. It should be better now, but beware !